Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 29
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Environ Manage ; 366: 121820, 2024 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-39003909

RESUMO

Northwest China has abundant solar energy resources and extensive land, making it a pivotal site for solar energy development. However, restrictions on site selection and severe weather conditions have hindered the establishment and operation of photovoltaic (PV) power stations. Previous studies have not considered meteorological factors when evaluating site suitability, leading to research gaps in identifying suitable areas and establishing indicator systems. We aimed to address these gaps by considering seven factors constraining the construction of centralized PV power stations (CPPS) and developing an indicator system based on terrain, climate, soil, and economic factors. Furthermore, we conducted analyses to quantify the solar energy generation potential (SEGP), carbon emissions reduction benefits, and land utilization potential at different sites. The findings indicate that areas rated as very suitable and extremely suitable comprised the largest proportion (62.35%) of site suitability. The correlation between site suitability and electricity consumption was largely non-significant, highlighting the need for enhanced coordination. Additionally, we forecast the electricity consumption in Xinjiang, Gansu, Inner Mongolia, Qinghai, Ningxia, and Shaanxi for 2030 to be 56.62, 19.86, 54.54, 13.59, 15.96, and 33.34 ( × 1011 kWh), respectively, with corresponding carbon emissions reduction potentials of 20.2, 7.1, 19.4, 4.8, 5.7, and 11.9 ( × 109 kg). Consequently, PV carbon reduction and land utilization potential are substantial.

2.
Arch Insect Biochem Physiol ; 116(3): e22129, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38973114

RESUMO

In beekeeping, when natural nectar or pollen sources become limited, it is crucial to provide supplemental bee feed to maintain the viability of the bee colony. This study was conducted during the autumn food shortage season, during which bees were fed with different proportions of modified bee feed. We identified an optimal bee diet by evaluating honeybee longevity, food consumption, body weight, and gut microbe distribution, with natural pollen serving as a control diet. The results indicated that bees preferred a mixture of 65% defatted soy flour, 20% corn protein powder, 13% wheat germ flour, 2% yeast powder, and a 50% sucrose solution. This bee food recipe significantly increased the longevity, feed consumption, and body weight of bees. The group fed the natural pollen diet exhibited a greater abundance of essential intestinal bacteria. The bee diets used in this study contained higher protein levels and lower concentrations of unsaturated fatty acids and vitamins than did the diets stored within the colonies. Therefore, we propose that incorporating both bee feed and natural pollen in beekeeping practices will achieve more balanced nutritional intake.


Assuntos
Ração Animal , Pólen , Abelhas/fisiologia , Animais , Ração Animal/análise , Dieta , Longevidade , Criação de Abelhas , Microbioma Gastrointestinal , Peso Corporal
3.
Food Res Int ; 190: 113905, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38945555

RESUMO

Bee bread is a product of honeybees, which collect and ferment pollen, that contains highly nutritious and easily digestible active substances. However, its nutritional composition varies significantly with fermentation strains and seasonal changes. To unveil the patterns of microbial community and nutritional component changes in bee bread across seasons, we employed high-throughput techniques to assess the diversity of bacteria and fungi in bee bread. The results indicated that the compositions of bacteria and fungi in bee bread undergo significant seasonal variation, with noticeable changes in the microbial diversity of bee bread from different bee species. Subsequently, metabolomic analysis revealed high activity of glycerophospholipid metabolism in bee bread. Furthermore, our analysis identifaied noteworthy differences in nutritional components, including pH values, sugar content, and free amino acid levels, in bee bread across different seasons.


Assuntos
Bactérias , Microbiota , Valor Nutritivo , Estações do Ano , Abelhas/microbiologia , Animais , Bactérias/classificação , Fermentação , Aminoácidos/análise , Fungos/classificação , Pólen/química , Pão/análise , Pão/microbiologia , Concentração de Íons de Hidrogênio , Metabolômica
4.
Int J Mol Sci ; 25(12)2024 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-38928075

RESUMO

In most cases, the number of honeybee stings received by the body is generally small, but honeybee stings can still cause serious allergic reactions. This study fully simulated bee stings under natural conditions and used 1H Nuclear Magnetic Resonance (1H NMR) to analyze the changes in the serum metabolome of Sprague-Dawley (SD) rats stung once or twice by honeybees to verify the impact of this mild sting on the body and its underlying mechanism. The differentially abundant metabolites between the blank control rats and the rats stung by honeybees included four amino acids (aspartate, glutamate, glutamine, and valine) and four organic acids (ascorbic acid, lactate, malate, and pyruvate). There was no separation between the sting groups, indicating that the impact of stinging once or twice on the serum metabolome was similar. Using the Principal Component Discriminant Analysis ( PCA-DA) and Variable Importance in Projection (VIP) methods, glucose, lactate, and pyruvate were identified to help distinguish between sting groups and non-sting groups. Metabolic pathway analysis revealed that four metabolic pathways, namely, the tricarboxylic acid cycle, pyruvate metabolism, glutamate metabolism, and alanine, aspartate, and glutamate metabolism, were significantly affected by bee stings. The above results can provide a theoretical basis for future epidemiological studies of bee stings and medical treatment of patients stung by honeybees.


Assuntos
Mordeduras e Picadas de Insetos , Metaboloma , Ratos Sprague-Dawley , Animais , Abelhas/metabolismo , Ratos , Mordeduras e Picadas de Insetos/sangue , Masculino , Redes e Vias Metabólicas , Análise de Componente Principal
5.
Heliyon ; 10(11): e31167, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38882348

RESUMO

Desertification constitutes a grave threat to the environmental and socio-economic stability of desertification frontline states in Northern Nigeria. From 2003 to 2020, this research comprehensively analyzes desertification vulnerability, integrating parameters such as NDVI, LST, TVDI, MSAVI, and Albedo. Key factors contributing to land degradation are identified, along with the spatial patterns and trends of desertification over the two-decade period. The consequences are profound, with Northern Nigeria's ecosystem experiencing a steady decline in vegetation cover. Agriculture, vital to the region's economy, faces increased aridity and reduced arable land, jeopardizing food security. Diminishing water resources exacerbates scarcity issues, placing additional strain on communities. These environmental changes lead to severe socio-economic implications, including displacement, loss of livelihoods, and heightened vulnerability to climate-related risks. Urgent, comprehensive, and strategic interventions are imperative. Policy recommendations underscore revising and enforcing land use regulations, promoting sustainable agricultural practices, and establishing monitoring systems to guide decision-making. This research contributes practical strategies to enhance the resilience of desertification frontline states, safeguard livelihoods, and align with Nigeria's sustainable development objectives. Findings from the study indicate that only a tiny percentage (6.7 %) of the study area remains unaffected by desertification. Moreover, 13.3 % exhibit light vulnerability, 20 % demonstrate moderate exposure, and 60 % fall into the severe (26.7 %) and compelling (33.3 %) vulnerability categories. These statistics underscore the gravity of desertification in the study area, emphasizing the urgent need for effective mitigation measures to address its impact comprehensively.

6.
Life (Basel) ; 14(3)2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38541665

RESUMO

The glands of bees are responsible for generating and secreting various biologically active substances that significantly impact bee physiological health and adaptability. This study aimed to investigate the effects of adding citric acid (CA) to bee feed on gland development and royal jelly quality. By formulating feed with varying proportions of CA, evaluation was undertaken of pollen feeding by honeybees under laboratory conditions, along with the impact of CA on the development of major glands, to determine suitable addition proportions. Further optimization of the CA proportion involved feeding colonies and evaluating royal jelly production and quality. The results indicated that feed containing 0.75% CA significantly extended the lifespan of bees and increased their pollen consumption. Gland development in bees showed a positive correlation with CA addition within the range of 0.25% to 0.75%, especially at 0.50% and 0.75%, which notably accelerated the development of mandibular, hypopharyngeal, and cephalic salivary glands, with active proliferation and differentiation of glandular cells and maintenance of normal gland size and morphology. CA added to feed stimulated vigorous secretion of wax glands in worker bees, resulting in prolific wax construction. Colonies consuming feed containing 0.50% CA produced royal jelly with significantly reduced moisture and total sugar content and increased levels of 10-HDA, total phenolic acids, total proteins, and acidity. These findings demonstrate that CA consumption significantly prolongs bee lifespan, increases consumption, promotes gland development, and enhances royal jelly quality. This research provides theoretical guidance for beekeeping practices and feed development, contributing to the sustainable advancement of apiculture.

7.
Arch Insect Biochem Physiol ; 115(3): e22104, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38506277

RESUMO

As a common defense mechanism in Hymenoptera, bee venom has complex components. Systematic and comprehensive analysis of bee venom components can aid in early evaluation, accurate diagnosis, and protection of organ function in humans in cases of bee stings. To determine the differences in bee venom composition and metabolic pathways between Apis cerana and Apis mellifera, proton nuclear magnetic resonance (1 H-NMR) technology was used to detect the metabolites in venom samples. A total of 74 metabolites were identified and structurally analyzed in the venom of A. cerana and A. mellifera. Differences in the composition and abundance of major components of bee venom from A. cerana and A. mellifera were mapped to four main metabolic pathways: valine, leucine and isoleucine biosynthesis; glycine, serine and threonine metabolism; alanine, aspartate and glutamate metabolism; and the tricarboxylic acid cycle. These findings indicated that the synthesis and metabolic activities of proteins or polypeptides in bee venom glands were different between A. cerana and A. mellifera. Pyruvate was highly activated in 3 selected metabolic pathways in A. mellifera, being much more dominant in A. mellifera venom than in A. cerana venom. These findings indicated that pyruvate in bee venom glands is involved in various life activities, such as biosynthesis and energy metabolism, by acting as a precursor substance or intermediate product.


Assuntos
Venenos de Abelha , Himenópteros , Mordeduras e Picadas de Insetos , Humanos , Abelhas , Animais , Ácido Pirúvico , Espectroscopia de Ressonância Magnética
8.
Sci Total Environ ; 926: 171846, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38513867

RESUMO

Chlorinated paraffins (CPs) are industrial chemicals that have potential adverse effects in the environment and on human health. This study investigated CPs in apiary environment, honeybees, and bee products from two rural areas of Beijing, China. The median concentrations of short-chain CPs (SCCPs) and medium-chain CPs (MCCPs) were 22 and 1.6 ng/m3 in the ambient air, 1350 and 708 ng/g dry mass (dw) in bees, 1050 and 427 ng/g dw in flowers, 37 and 54 ng/g in honey, 78 and 53 ng/g dw in bee pollen, 36 and 30 ng/g dw in soil, and 293 and 319 ng/g dw in bee wax. C10Cl6-7 and C14Cl7-8 dominated SCCPs and MCCPs in these samples, respectively. The concentrations and distributions of CPs in samples from apiaries located in the two regions varied. Long-range transportation of air masses was identified as an important source of CPs in apiaries. A close relationship between CPs in bees and the apiary environment indicated that bees could act as bioindicators for CP contamination in the environment. A human health risk assessment found that there were low risks for adults and children exposed to CPs through consumption of honey and pollen from the studied regions.


Assuntos
Hidrocarbonetos Clorados , Parafina , Criança , Abelhas , Humanos , Animais , Parafina/análise , Monitoramento Ambiental , Hidrocarbonetos Clorados/análise , China , Pequim
9.
Heliyon ; 9(9): e19251, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37674844

RESUMO

A microseismic localization algorithm that combines global search and local optimization is proposed. The Fewer Conditions Trigger Difference (FCTD) objective function of global search and local optimization is constructed, the execution process of the algorithm is described by numerical simulation, and the global search and local optimization microseismic localization algorithm is verified and applied by field data analysis. The results show that: (1) the global search and local optimization methods have fast search speed in the global range, high convergence accuracy and stable localization results in the local range, and high localization accuracy and stability without relying on the velocity model and initial values in the process of search. (2) By comparing the localization results of different localization methods, the global search and local optimization algorithms have better localization results.

10.
Insects ; 14(6)2023 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-37367370

RESUMO

There is growing concern that massive loss of honey bees can cause serious negative effects on biodiversity and ecosystems. Surveys of colony losses have been performed worldwide to monitor the dynamic changes and health status of honey bee colonies. Here, we present the results of surveys regarding winter colony losses from 21 provinces in China from 2009 to 2021, with a total of 1,744,324 colonies managed by 13,704 beekeepers. The total colony losses were low (9.84%; 95% Confidence Interval (CI): 9.60-10.08%) but varied among years, provinces, and scales of apiaries. As little is known about the overwintering mortality of Apis cerana, in this study, we surveyed and compared the loss rates between Apis mellifera and A. cerana in China. We found colonies of A. mellifera suffered significantly lower losses than A. cerana in China. Larger apiaries resulted in higher losses in A. mellifera, whereas the opposite was observed in A. cerana. Furthermore, we used generalized linear mixed-effects models (GLMMs) to evaluate the effects of potential risk factors on winter colony losses and found that the operation size, species, migration, migration×species interaction, and queen problems were significantly related to the loss rates. New queens can increase their colony overwintering survival. Migratory beekeepers and large operations reported lower loss rates.

11.
Toxicon ; 231: 107196, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37348820

RESUMO

With the development of beekeeping, the risk of bee stings in humans is increasing. Severe and life-threatening toxic reactions can occur after multiple bee stings, and their pathogenesis has not been elucidated. To understand the effect of multiple bees (Apis mellifera) stings on the organism in a short period, we stung rats once and five times, respectively. Serum and organs were obtained after 3 h for analysis. The results indicated that skin erythema was more pronounced and hemolysis was more severe as the number of puncture wounds increased. After being stung by five bees, rats had dramatically higher serum levels of direct bilirubin, aspartate aminotransferase, creatine kinase and lactate dehydrogenase, producing more differential metabolites that affected mainly four metabolic pathways. In addition, the liver, kidney and heart showed significant congestion and inflammation. This study helps explain the organism's clinical response to bee venom and may be valuable in treating toxic reactions following bee stings.


Assuntos
Venenos de Abelha , Mordeduras e Picadas de Insetos , Humanos , Abelhas , Animais , Ratos , Ratos Sprague-Dawley , Venenos de Abelha/toxicidade
12.
Environ Microbiol ; 25(10): 2020-2031, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37291689

RESUMO

Honeybee (Apis mellifera) ingestion of toxic nectar plants can threaten their health and survival. However, little is known about how to help honeybees mitigate the effects of toxic nectar plant poisoning. We exposed honeybees to different concentrations of Bidens pilosa flower extracts and found that B. pilosa exposure significantly reduced honeybee survival in a dose-dependent manner. By measuring changes in detoxification and antioxidant enzymes and the gut microbiome, we found that superoxide dismutase, glutathione-S-transferase and carboxylesterase activities were significantly activated with increasing concentrations of B. pilosa and that different concentrations of B. pilosa exposure changed the structure of the honeybee gut microbiome, causing a significant reduction in the abundance of Bartonella (p < 0.001) and an increase in Lactobacillus. Importantly, by using Germ-Free bees, we found that colonization by the gut microbes Bartonella apis and Apilactobacillus kunkeei (original classification as Lactobacillus kunkeei) significantly increased the resistance of honeybees to B. pilosa and significantly upregulated bee-associated immune genes. These results suggest that honeybee detoxification systems possess a level of resistance to the toxic nectar plant B. pilosa and that the gut microbes B. apis and A. kunkeei may augment resistance to B. pilosa stress by improving host immunity.


Assuntos
Bidens , Microbioma Gastrointestinal , Abelhas , Animais , Microbioma Gastrointestinal/genética , Néctar de Plantas/farmacologia , Flores
13.
Environ Pollut ; 314: 120225, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36150626

RESUMO

Polychlorinated naphthalenes (PCNs) are highly toxic and persistent organic pollutants that can cause adverse effects in the environment and on human health. PCNs have been detected in remote areas because of their long-range transportation. Bees and bee products are commonly used as biomonitors for various pollutants in the environment. However, information on PCNs in apiaries is scarce. The aim of this study was to evaluate the occurrences of PCNs in bees and bee products from apiaries located in different geographical regions of China, and to identify potential pollution sources and assess exposure risks to humans. Our results showed that the average Σ75PCNs concentrations in bees, pollen, and wax were 74.1, 96.3, and 141 pg/g dry weight, respectively. The homologue and congener profiles of PCNs in bees, pollen, and wax were similar, and di- and tri-chlorinated naphthalenes (>60%) were the predominant homologues. The concentrations and distributions of PCNs in bees, pollen, and wax varied among different geographical regions, but their occurrences were correlated with PCN metallurgical sources in China. The health risks of PCNs in pollen were evaluated, and both carcinogenic and non-carcinogenic risks of PCNs exposure to humans through the diet were low.


Assuntos
Monitoramento Ambiental , Poluentes Ambientais , Animais , Humanos , Abelhas , China , Naftalenos/análise , Poluentes Orgânicos Persistentes , Pólen/química
14.
Nutrients ; 14(16)2022 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-36014951

RESUMO

Honey is proposed to be the oldest natural sweetener and it is a standard component of several dietary patterns. Recent evidence suggests that replacing sugars, such as fructose, with honey has potential health benefits. In this study, we determined the effects of honey supplementation in mice on cardiometabolic and inflammatory markers and changes in gut microbiota and metabolomic profiles. We compared mice fed a honey diet (1 or 2 g/kg) with those fed an analog diet (mixed fructose, glucose, and sucrose (FSG) solutions) at exact dosages for one month. We found the same blood glucose fluctuating trends for honey- and FGS-fed mice. The honey diets resulted in less weight gain and fewer ballooned hepatocytes. Additionally, honey diets decreased the total serum cholesterol and TNF-α and increased the antioxidant enzyme activity. Each diet type was associated with distinct gut microbiota and metabolomics profiles. Systems biology analysis revealed that Lactococcus spp., Lachnospiraceae spp., and oleamide had the strongest correlations with lipid metabolic networks. Although in an animal model, this study provides a good understanding of the potential benefits of choosing honey rather than mixed sugars in regular dietary patterns.


Assuntos
Mel , Animais , Frutose/farmacologia , Mel/análise , Camundongos , Açúcares , Biologia de Sistemas , Aumento de Peso
15.
J Agric Food Chem ; 68(13): 4062-4071, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32186876

RESUMO

Harvesting uncapped immature honey (IMH) followed by dehydration is a typical counterfeit honey production process, but the differences between IMH and capped mature honey (MH) have not been well described previously. In this study, MH and IMH from Apis mellifera colonies during the same rapeseed flower season were compared. MH was found to have lower water content, lower acidity, and higher fructose content. High-performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry-based untargeted metabolomic analysis indicated that MH had a distinct metabolite composition to IMH. Targeted metabolomic analysis on 20 major polyphenolic constituents showed higher accumulation in MH. MH had greater bacteriostatic effect and stronger free radical scavenging effect. While both the honeys mitigated cell damage caused by H2O2, the effective dosage of IMH was higher and its inducing effect on the antioxidant gene expression was weaker. Overall, MH was shown to be of better quality than IMH not only because of its richer polyphenolic composition but also because of its stronger biological activity.


Assuntos
Mel/análise , Animais , Antioxidantes , Abelhas/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Manipulação de Alimentos , Concentração de Íons de Hidrogênio , Espectrometria de Massas/métodos , Metabolômica/métodos , Polifenóis/química , Estações do Ano
16.
Waste Manag ; 99: 163-171, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31494352

RESUMO

In order to seek a safe, sustainable, and low-cost method for reuse of municipal sewage sludge, four species of native plants, i.e., Forsythia suspensa, Sophora japonica, Cotinus coggygria, and Ailanthus altissima were planted in flowerpots containing 4 growth substrates consisting of raw sludge and fly ash at volume/volume ratios of 20:80, 40:60, 60:40, and 80:20, respectively. The results showed that the physiochemical characteristics of the sewage sludge and fly ash were complementary. The sludge supplied the nutrients and the fly ash maintained air permeability in the mixed substrate. The mixed substrates containing 40-60% sewage sludge that belonged to sand clay loam were suitable for the seedling growth of the four species. After the end of the growing season, the electrical conductivity, pH, and contents of organic matter, nitrogen, potassium, and heavy metals in the four growth substrates decreased significantly. Moreover, most of the heavy metals were removed from the substrates by seedling root system. A. altissima grew best, and heavy metal enrichments of F. suspense and C. coggygria were stronger than other two species. The results indicate that the new substrates containing 40-60% sludge exhibiting good physiochemical properties, are environmentally friendly, and suitable for landscape planting.


Assuntos
Cinza de Carvão , Metais Pesados , Nitrogênio , Plantas , Esgotos
17.
J Exp Biol ; 222(Pt 7)2019 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-30846535

RESUMO

Nutrition is involved in regulating multiple aspects of honey bee biology such as caste, immunity, lifespan, growth and behavioral development. Deformed wing virus (DWV) is a major pathogenic factor which threatens honey bee populations, and its replication is regulated by the nutrition status and immune response of honey bees. The alimentary canal of the honey bee is home to a diverse microbial community that provides essential nutrients and serves to bolster immune responses. However, to what extent gut bacteria affect honey bee nutrition metabolism and immunity with respect to DWV has not been investigated fully. In this study, newly emerged worker bees were subjected to four diets that contained (1) pollen, (2) pollen and antibiotics, (3) neither pollen nor antibiotics or (4) antibiotics alone. The expression level of two nutrition genes target of rapamycin (tor) and insulin like peptide (ilp1), one nutritional marker gene vitellogenin (vg), five major royal jellyprotein genes (mrjp1-5), one antimicrobial peptide regulating gene relish (rel), and DWV virus titer and its replication intermediate, negative RNA strand, were determined by qRT-PCR from the honey bees at 7 days post-antibiotic treatment. Additionally, honey bee head mass and survival rate were measured. We observed that antibiotics decreased the expression of tor and rel, and increased DWV titer and its replication activity. Expression of ilp1, mrjp1-5 and vg, and honey bee head mass were also reduced compared with bees on a pollen diet. Antibiotics also caused a significant drop in survivorship, which could be rescued by addition of pollen to the diet. Of importance, pollen could partially rescue the loss of vg and mrjp2 while also increasing the head mass of antibiotic-treated bees. Our results illuminate the roles of bacteria in honey bee nutrition, metabolism and immunity, which confer the ability to inhibit virus replication, extend honey bee lifespan and improve overall health.


Assuntos
Bactérias/isolamento & purificação , Abelhas/imunologia , Abelhas/microbiologia , Pólen , Fenômenos Fisiológicos da Nutrição Animal , Animais , Antibacterianos/administração & dosagem , Bactérias/classificação , Bactérias/efeitos dos fármacos , Abelhas/virologia , Dieta , Feminino , Microbioma Gastrointestinal/efeitos dos fármacos , Expressão Gênica , Cabeça/anatomia & histologia , Penicilinas/administração & dosagem , Vírus de RNA/crescimento & desenvolvimento , Estreptomicina/administração & dosagem
18.
Sci Total Environ ; 667: 435-443, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-30833242

RESUMO

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are two types of perfluorinated compounds (PFCs) frequently studied in recent years due to their potential for bioaccumulation and toxicity to humans. Usually, PFCs can co-exist in various environment. Therefore, over- or under-estimated risk assessments would result if antagonism or synergism occurred in mixture toxicity. In the present study, the acute and chronic toxicities of single and mixtures of PFOA and PFOS to Daphnia magna were investigated. PFOS was more toxic than PFOA, both in 48-h acute toxicity and 21-d chronic toxicity. In acute toxicity tests, mixture toxicities showed strong synergistic effects on mortality. The experimental EC50 of the mixture is 4.44 × 10-5 mol/L, whereas the predicted EC50 is 8.19 × 10-5 mol/L by Concentration Addition Model and 9.73 × 10-5 mol/L by Independent Action Model. In chronic toxicity tests, synergistic effects were also found in the aspects of offspring. The offspring rate is reduced significantly to 39.8% at the 9.61 × 10-7 mol/L of mixture, while, PFOS and PFOA do not have effects when they are tested individually at corresponding concentrations. To explore the potential mechanism of the synergistic effect, the interactions between PFCs and proteins, including acetylcholinesterase, superoxide dismutase, catalase, ecdysone receptor and glutathione-S-transferase, were investigated by the Molecular Docking. The docking results revealed that the driving forces for the binding of PFCs with proteins were predominantly hydrophobic and hydrogen-bonding interactions. Based on the binding models, we deduced that the potential mechanism of synergism is that PFOS and PFOA have similar binding modes with catalase and have different binding modes with superoxide dismutase. Overall, these data provide experimental evidence that there is strong synergism in acute and chronic toxicity of mixtures to D. magna and demonstrate that molecular structure of some components of the antioxidant defence system contributes to the synergistic interaction.


Assuntos
Ácidos Alcanossulfônicos/toxicidade , Daphnia/fisiologia , Fluorocarbonos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Antioxidantes , Caprilatos , Catalase/metabolismo , Superóxido Dismutase/metabolismo , Testes de Toxicidade Crônica
19.
Viruses ; 11(1)2019 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-30646581

RESUMO

RNA viruses that contain single-stranded RNA genomes of positive sense make up the largest group of pathogens infecting honey bees. Sacbrood virus (SBV) is one of the most widely distributed honey bee viruses and infects the larvae of honey bees, resulting in failure to pupate and death. Among all of the viruses infecting honey bees, SBV has the greatest number of complete genomes isolated from both European honey bees Apis mellifera and Asian honey bees A. cerana worldwide. To enhance our understanding of the evolution and pathogenicity of SBV, in this study, we present the first report of whole genome sequences of two U.S. strains of SBV. The complete genome sequences of the two U.S. SBV strains were deposited in GenBank under accession numbers: MG545286.1 and MG545287.1. Both SBV strains show the typical genomic features of the Iflaviridae family. The phylogenetic analysis of the single polyprotein coding region of the U.S. strains, and other GenBank SBV submissions revealed that SBV strains split into two distinct lineages, possibly reflecting host affiliation. The phylogenetic analysis based on the 5'UTR revealed a monophyletic clade with the deep parts of the tree occupied by SBV strains from both A. cerane and A. mellifera, and the tips of branches of the tree occupied by SBV strains from A. mellifera. The study of the cold stress on the pathogenesis of the SBV infection showed that cold stress could have profound effects on sacbrood disease severity manifested by increased mortality of infected larvae. This result suggests that the high prevalence of sacbrood disease in early spring may be due to the fluctuating temperatures during the season. This study will contribute to a better understanding of the evolution and pathogenesis of SBV infection in honey bees, and have important epidemiological relevance.


Assuntos
Abelhas/virologia , Genoma Viral , Vírus de Insetos/genética , Filogenia , Vírus de RNA/patogenicidade , Animais , Resposta ao Choque Frio , Variação Genética , Vírus de Insetos/patogenicidade , Infecções por Vírus de RNA , Vírus de RNA/genética , Estados Unidos , Sequenciamento Completo do Genoma
20.
Insects ; 10(1)2019 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-30626033

RESUMO

The synergistic interactions between the ectoparasitic mite Varroa destructor and Deformed wing virus (DWV) lead to the reduction in lifespan of the European honey bee Apis mellifera and often have been implicated in colony losses worldwide. However, to date, the underlying processes and mechanisms that form the multipartite interaction between the bee, mite, and virus have not been fully explained. To gain a better understanding of honey bees' defense response to Varroa mite infestation and DWV infection, the DWV titers and transcription profiles of genes originating from RNAi, immunity, wound response, and homeostatic signaling pathways were monitored over a period of eight days. With respect to DWV, we observed low viral titers at early timepoints that coincided with high levels of Toll pathway transcription factor Dorsal, and its downstream immune effector molecules Hymenoptaecin, Apidaecin, Abaecin, and Defensin 1. However, we observed a striking increase in viral titers beginning after two days that coincided with a decrease in Dorsal levels and its corresponding immune effector molecules, and the small ubiquitin-like modifier (SUMO) ligase repressor of Dorsal, PIAS3. We observed a similar expression pattern for genes expressing transcripts for the RNA interference (Dicer/Argonaute), wound/homeostatic (Janus Kinase), and tissue growth (Map kinase/Wnt) pathways. Our results demonstrate that on a whole, honey bees are able to mount an immediate, albeit, temporally limited, immune and homeostatic response to Varroa and DWV infections, after which downregulation of these pathways leaves the bee vulnerable to expansive viral replication. The critical insights into the defense response upon Varroa and DWV challenges generated in this study may serve as a solid base for future research on the development of effective and efficient disease management strategies in honey bees.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...